I've seen groups close to an inch at 100 with an Eliminator.

Baz has posted of hitting shotgun cases regularly at that distance with some Theoben or other

Sid or Craig have pulled of something close with a Career

It can certainly be done with an FAC airgun at 100 but I suspect is very sensitive to hold, rifle consistency and ammunition performance.

After all with a centrefire its commonplace so the human element is definately do-able its velocity consistency, wind variation and bc that are the killers

Richard